In third degree AV block, there is complete absence of AV conduction. The sinus impulses do not activate the ventricle. There is AV dissociation with varying PR intervals, and the atrial rate is usually greater than the ventricular rate. The escape rhythm QRS is regular and originates just below the block, in the AV node, His bundle, bundle branches, or the ventricles. By convention, we designate escape rhythms as junctional or ventricular. Escape junctional rhythms usually have narrow QRS complexes, with rates in the 35-60 per minute range. Escape ventricular rhythms are characterized by QRS complexes that are regular and wide, different from the patient’s sinus complexes, and at a rate of 20 to 50 bpm. The following animation illustrates what we have just described. Note in the animation the complete block is in the bundle branches.